Ametek JOFRA ATC-125 - Page 25

122770 06 18-09-2007 25
Error: Calibrator does not cool or heat sufficiently or
is slower than specified (ATC-125 only).
Error message:
-
Likely cause: Solution:
Set the calibrator to –90°C
Check voltages on test pins:
Between GND and 24V >23V
Between GND and TC_Well 1,4V+(6.20 mV/°C x T)
Between GND and PWM >1V and <2V
Between GND and TC_SMH 0,8V+(6.20 mV/°C x T)
Between GND and SAFE >4,5V
Defective Power PCB
Set the SET temperature to 125°C. On the
Power PCB measure the voltage between
test pin 24V and GND.
If the voltage is less than 23V, pull out
CN103 and re-measure. If the voltage still is
too low, check fuse F3 on Power PCB, else
replace Power PCB.
If pulling out CN103 re-establishes the 24V,
the Stirling Controller PCB is defect.
Defect safety
thermocouples
If “Safe” is low, check “TC_Well” or
“TC_SMH”. If defective replace the sensor.
Broken ribbon cable
If the PWM signal is missing, the 34-poled
ribbon cable between Main Board and
Power Board is broken or the Main Board is
defect.